/* 
GeoGebra - Dynamic Mathematics for Everyone
http://www.geogebra.org

This file is part of GeoGebra.

This program is free software; you can redistribute it and/or modify it 
under the terms of the GNU General Public License as published by 
the Free Software Foundation.

 */

package org.geogebra.common.kernel.algos;

import org.geogebra.common.kernel.Construction;
import org.geogebra.common.kernel.StringTemplate;
import org.geogebra.common.kernel.arithmetic.ExpressionNode;
import org.geogebra.common.kernel.arithmetic.ExpressionNodeConstants.StringType;
import org.geogebra.common.kernel.arithmetic.ExpressionValue;
import org.geogebra.common.kernel.arithmetic.FunctionNVar;
import org.geogebra.common.kernel.geos.GeoFunctionNVar;
import org.geogebra.common.util.debug.Log;

/**
 * This class is needed to handle dependent multivariate functions like e.g.
 * f(x,y) = a x^2 + b y that depends on a and b.
 * 
 * @author Markus Hohenwarter
 */
public class AlgoDependentFunctionNVar extends AlgoElement
		implements DependentAlgo {

	private FunctionNVar fun;
	private GeoFunctionNVar f; // output
	private ExpressionNode expression;
	private FunctionNVar expandedFun;
	private boolean expContainsFunctions;

	/**
	 * @param cons
	 *            construction
	 * @param label
	 *            label for output
	 * @param fun
	 *            input function
	 */
	public AlgoDependentFunctionNVar(Construction cons, String label,
			FunctionNVar fun) {
		this(cons, fun);
		f.setLabel(label);
	}

	/**
	 * @param cons
	 *            construction
	 * @param fun
	 *            input function
	 */
	AlgoDependentFunctionNVar(Construction cons, FunctionNVar fun) {
		super(cons, false);
		fun.initFunction();
		cons.addToConstructionList(this, false);
		this.fun = fun;
		f = new GeoFunctionNVar(cons, false);
		f.setFunction(fun);

		expression = fun.getExpression();
		expContainsFunctions = AlgoDependentFunction
				.containsFunctions(expression);
		if (expContainsFunctions) {
			expandedFun = new FunctionNVar(fun, kernel);
		}
		setInputOutput(); // for AlgoElement
		compute();
		f.setConstructionDefaults();
	}

	@Override
	public Algos getClassName() {
		return Algos.Expression;
	}

	// for AlgoElement
	@Override
	protected void setInputOutput() {
		input = fun.getGeoElementVariables();

		setOutputLength(1);
		setOutput(0, f);
		setDependencies(); // done by AlgoElement
	}

	/**
	 * @return resulting function
	 */
	public GeoFunctionNVar getFunction() {
		return f;
	}

	@Override
	public final void compute() {
		// evaluation of function will be done in view (see
		// geogebra.euclidian.DrawFunction)

		// check if function is defined
		boolean isDefined = true;
		for (int i = 0; i < input.length; i++) {
			if (!input[i].isDefined()) {
				isDefined = false;
				break;
			}
		}
		if (isDefined && expContainsFunctions) {
			// expand the functions and derivatives in expression tree
			ExpressionValue ev = null;

			try { // needed for eg f(x)=floor(x) f'(x)
				ev = AlgoDependentFunction.expandFunctionDerivativeNodes(
						expression.deepCopy(kernel), false);
			} catch (Exception e) {
				e.printStackTrace();
				Log.debug("derivative failed");
			}

			if (ev == null) {
				f.setUndefined();
				return;
			}

			ExpressionNode node;
			if (ev.isExpressionNode()) {
				node = (ExpressionNode) ev;
			} else {
				node = new ExpressionNode(kernel, ev);
			}

			expandedFun.setExpression(node);
			f.setFunction(expandedFun);
			// we need this to update the borders, see #2880
			if (f.isBooleanFunction() && f.isLabelSet()) {
				f.resetIneqs();
			}
		}

		f.setDefined(isDefined);
	}

	private StringBuilder sb;

	@Override
	public String toString(StringTemplate tpl) {
		if (sb == null) {
			sb = new StringBuilder();
		} else {
			sb.setLength(0);
		}
		if (f.isLabelSet() && !tpl.isHideLHS() && (!f.isBooleanFunction()
				|| tpl.hasType(StringType.GEOGEBRA_XML))) {
			sb.append(f.getLabel(tpl));
			sb.append("(");
			sb.append(f.getVarString(tpl));
			sb.append(") = ");
		}
		sb.append(fun.toString(tpl));
		return sb.toString();
	}

	@Override
	public ExpressionNode getExpression() {
		return expression;
	}

}